Dropdown Boxes

The standard HTML dropdown box is fine if you only have, say, 20 values to choose from, but what about when you want to select a foreign key from, say, 70,000 possible values? Then it’s just annoying.

What do you use? I’ve found the Kartik Select2 widget that looks promising, but what else is available?

Also, are there any CRUD generators or templates that automatically use this kind of dropdown box for foreign keys?

Any advice or comments are welcome. I’m still a YII newbie and need all the help I can get.